At first glance, even second glance, Bletchley Park could easily be just another beautiful British building deserving of some loving care and attention. But for many years its walls guarded one of the best kept secrets of the 20th Century. During the Second World War it was the top secret home to the cryptanalysts, mathematicians and military personnel later credited with shortening the war by at least two years and saving millions of lives by breaking the secret ciphers used in Nazi communications. Seventy years after war was declared on Germany, Gizmag's Paul Ridden takes a closer look at what went on at HMS Pembroke V, the people who worked there and talks to some of the those now dedicated to ensuring that its legacy lives on.